Pressure accumulator

ABSTRACT

This invention relates to the art of pressure vessels, more particularly of the type having a rigid container with a deformable bladder therein dividing the container into two variable volume chambers, each adapted to receive fluid under pressure. A port is in communication with one of said chambers and a valve member mounted axially on the bladder and molded integrally therewith is associated with said port to close the latter. The valve member is molded into the bladder in such manner that the force exerted by the compressed gas in the bladder will exert a minimum of shearing stress against the molded junction of the valve member to the associated end of the bladder to prevent shearing. In addition, the valve member has a portion extending axially behond the molded junction thereby eliminating impact against such molded junction when the valve member seats to close the port.

limited States Patent [1 1 Zahid Feb. l9, W74

[ PRESSURE ACCUMULATOR {75] Inventor: Abdul Zahid, Monterey Park, Calif.

[73] Assignee: Greer Hydraulics, Inc., Los Angeles,

Calif.

{22] Filed: July 2%, 11972 [21] Appl. No.: 276,147

Primary Examiner-George E. Lowrance Assistant Examiner steven M. Pollard ASSTRKCT This invention relates to the art of pressure vessels, more particularly of the type having a rigid container with a deformable bladder therein dividing the container into two variable volume chambers, each adapted to receive fluid under pressure. A port is in communication with one of said chambers and a valve member mounted axially on the bladder and molded integrally therewith is associated with said port to close the latter. The valve member is molded into the bladder in such manner that the force exerted by the compressed gas in the bladder will exert a minimum of shearing stress against the molded junction of the valve member to the associated end of the bladder to prevent shearing. In addition, the valve member has a portion extending axially behond the molded junction thereby eliminating impact against such molded junction when the valve member seats to close the port.

8 Claims, 3 Drawing Figures Attorney, Agent, or firm Arthur B. Colvin PAIENI mu 9 1914 PRESSURE ACCUMULATOR As conducive to an understanding of the invention, it is noted that in pressure vessels of the above type where the valve member is in the form of a button molded at the free end of a bladder which has its opposed end securely mounted to the container, it is essential that the valve member not be subjected to shearing action due to the force exerted by the compressed gas in the bladder, particularly against the bonded junction of the valve member to the bladder. If such shearing action occurs, there will be a tendency for the bladder material to separate from the valve member or button with resultant tearing of the bladder and failure of the unit.

Furthermore, in operation of an accumulator of the above type, the valve member or button will strike against the valve seat defined by the periphery of the oil port to close the latter and as such operation happens many times during cycling of the accumulator in use, where the bonded area is subjected to such constant impacts, it is likely to fail with resultant failure of the unit.

It is accordingly among the objects of the invention to provide a pressure accumulator of the above type in which the valve member or button may readily be molded integrally with the bladder with assurance that the molded junction between the periphery of the valve member and the bladder will not be subjected to shearing stress and furthermore, with assurance that when the bladder seats to close the oil port, the impact of such closing action against the molded junction of the bladder to the valve member will be substantially minimized.

According to the invention these objects are accomplished by the arrangement and combination of elements hereinafter described and more particularly recited in the claims.

In the accompanying drawings in which are shown one of various possible embodiments of the several features of the invention;

FIG. 1 is a perspective view of a pressure vessel according to the invention;

FIG. 2 is a sectional view on a greatly enlarged scale with parts broken away taken along line 2--2 of FIG. 1, and i I FIG. 3 is a sectional view on a further enlarged scale showing the valve member and associated port.

Referring now to the drawings, the pressure vessel illustratively comprises a substantially cylindrical container 1 l of rigid material such as steel or aluminum capable of withstanding the pressure to which it is to be subjected in use.

The container has one end closed as at 12 and such closed end has an axial port 13, the inner end 14 of which defines a valve seat. The mouth 15 of the container is cylindrical as shown and the inner surface of the container adjacent the mouth 15 is threaded as at 16. An annular groove 17 is provided in the inner surface of the container adjacent the inner end of the threaded portion 16 and such annular groove 17 is in communication with the exterior of the unit through transverse passageway 18.

The inner diameter of the container is of lesser diameter than the diameter of the threaded portion 16 as is clearly shown at 19 and the annular portion of the inner surface of the container from the reduced diameter portion 19 to the annular groove 17 is beveled outwardly as at 21 to define an annular clearance 22.

Positioned in the container 11. is a deformable partition illustratively in the form of an elongated bladder 23 of rubber or similar material having like characteristics, which dividesthe container 11 into two chambers C and C-1. The bladder 23 is closed at one end as at 24 and the mouth 25 of the bladder which is of greater thickness than the remaining portion of the bladder is secured as by molding to an annular supporting member 26 of rigid material, preferably of steel. By reason of the molding of the bladder 23 to the annular supporting member 26, the bladder 23 will be securely bonded to such supporting member 26.

As is clearly shown in FIG. 2, the annular supporting member 26 is substantially rectangular in cross section, illustratively having a flat top wall 27 and a depending annular flange 28 with an outwardly extending lip 29 integral with its flat inner surface 31.

As a result of the foregoing construction, not only will the bonding of the thickened rim of the bladder to the annular supporting member retain the elements in juxtaposition, but the outwardly extending annular lip 29 will insure such retention.

It is to be noted that the transverse width of the annular supporting member is greater than that of the thickened rim 25 of the bladder so that as clearly shown in FIG. 2, the outer periphery 32 of the annular supporting member 26 will extend laterally outwardly of the outer periphery 33 of the thickened rim 25.

As is also clearly shown in FIG. 2, the inner diameter of the container is still further reduced to define an annular shoulder 34 which forms a seat for the outer periphery 32 of the annular supporting member 26 so that the bladder 23 will be dependablyretained in desired position in the container.

The annular supporting member 26 has an annular groove 35 in its outer periphery in which an O-ring 36 is positioned, the function of the O-ring being to provide a seal.

In order to retain the annular supporting member 26 and bladder 23 in position, a cylindrical cover member 38 is provided. As'is clearly shown in the drawing, the cover member is substantially cup-shaped with its side wall or skirt 39 of outer diameter just slightly less than the diameter of the reduced portion 19 of the container so that the side wall 39 may readily be positioned in the container.

The cover member 38 adjacent its outer surface is of slightly enlarged diameter as at 41 and is externally threaded so that the cover member may be screwed into threaded mouth 16 of the container by means of a spanner wrench (not shown) applied to conventional bores 42' in the top surface 42 of the cover member 38.

As is clearly shown in the drawings, when the cover member is screwed into the container so that the top surface 42 of the cover member is flush with the outer end 15 of the container, the inner end 43 of the side wall 39 of the cover member will abut against the top surface 27 of the annular supporting member 26 to retain the latter on the annular shoulder 34. The outer periphery of the side wall 39 of the cover member has an annular groove 44 in which an O-ring 45 is positioned to define a seal between the side wall 39 and the inner surface of the container.

It is to be noted that with the cover member screwed in place as shown in FIG. 2, the inner end 46 of the enwith the outer edge of the annular groove 17.

To complete the assembly, the cover member has an axial bore 51 in which a conventional gas charging valve 52 may be positioned, the latter having a removable cap 53 associated therewith to protect the charging valve 52.

Mounted on the closed end 24 of the bladder 23 and axially positioned with respect thereto is a valve member 54 illustratively in the form of a button, preferably formed from steel or aluminum.

According to the invention, the valve member illustratively is in the form of a disc having a top portion 55 with a rounded periphery 55' and has a reduced diameter portion 56 defining a cylindrical side wall 57, the outer periphery of the top portion 55 of the valve member extending laterally outward beyond the side wall 57 to define an annular flange 58.

In addition, the valve member 54 has a further reduced diameter portion 61 defining a second cylindrical side wall 62 and an annular shoulder 63. The surface 68 of reduced diameter portion 61 defines the abutment surface of the valve member, the latter having a plurality of diametric grooves 71, the function of which will be hereinafter described.

As is clearly shown in the drawings, the valve member 54 is molded integrally with the end 24 of the bladder so as to be axially aligned therewith. As shown, a layer 65 of bladder material will extend across the top surface 66 of the valve member. The cylindrical side 3 wall 57 of the valve member as well as the top surface 66 and the rounded periphery 55 and the undersurface of flange 58 are coated with a bonding agent prior to molding and the bladder material is bonded to said side wall 57 as well as to the bottom surface, rounded periphery and top surfaces of the flange 58. It is to be noted that the outer surface of the portion 67 of the bladder is aligned with the shoulder 63 so that the cylindrical portion 62 of the valve member will protrude axially outwardly from the end of the bladder.

lnconventional manner the bladder 23 may be precharged with gas under pressure through valve 52.. As a result, the bladder will expand and the periphery 68 of the undersurface of the valve member will move against the seat S defined by the periphery of the port 13 to close said port. A fluid such as liquid under pressure is forced into chamber C-l through a valve (not shown) controlling port 13, to compress the gas in chamber C.

In the event of premature closure of the valve member in use of the accumulator, before substantially all of the liquid is discharged from chamber C-l, by reason of the diametric grooves 71, a slight discharge will still be provided to insure that in the subsequent cycle, the desired gas pressure and volume will be maintained.

It is to be noted that the force of the compressed gas in the bladder shown by the arrows in FIG. 2, will not be exerted against the bonded junction of the bladder against the cylindrical wall 57 since the lateral flange 55 of the button will protect the bonded junction at cylindrical wall 57.

As a result, due to the avoidance of such shearing stress, the likelihood of tearing of the bladder or breaking of the bond at such junction is minimized if not predluded.

Furthermore, it is to be noted that the annular contact region defined by the periphery 68 of the undersurface of the valve member extends axially beyond the bonded junction of the bladder to the cylindrical wall 57. Consequently, during operation, onlythe rigid metal undersurface of the valve member will be subjected to impact when it strikes the seat S defined by the periphery of port 13. As a result, no direct impact will be imparted to the bonded junction at 57 which could cause a crack to start which would quickly extend through the entire thickness of the bladder wall causing failure of the bladder.

By reason of the cylindrical configuration of the side wall 57 of the valve member and the plane shoulder 63, in molding of the valve member 54 with the bladder, there is assurance that the bladder material will bond securely to the entire cylindrical side wall 57 because there is no possibility of pressure leakage so that a secure bond can be achieved.

With the unique construction above described, the valve member will remain securely bonded to the end of the bladder without likelihood of breakage of the bond, even after long repeated use of the pressure accumulator.

I claim:

1. A pressure vessel comprising a container of rigid material having two ports, one of said ports being axially aligned with said container and defining a liquid port, a deformable bladder secured in said container and separating said two ports from each other to define two variable volume fluid receiving chambers, one of said chambers being in communication with said liquid port, said bladder extending axially in said container and being closed at one end, means to charge said bladder with gas under pressure through the other of said ports, the portion of the container adjacent the periphery of the liquid port defining a valve seat, a valve member molded in the closed end of said bladder and axially aligned therewith adapted to move against said valve seat to close said liquid port, said valve member comprising a disc having an abutment surface adapted to engage said valve seat and having a reduced diameter portion extending axially outward therefrom defin ing a laterally extending annular flange of greater diameter than the abutment surface of said disc, said reduced diameter portion having a side wall to which the bladder material is bonded, said flange being interposed between the interior of said bladder and the bonded junction of the bladder material to said side wall.

2. The combination set forth in claim 1 in which the periphery of said flange is rounded.

3. The combination set forth in claim 1 in which a layer of bladder material extends over the surface of said disc and around the periphery and undersurface of said flange and said bladder material is bonded to the surface of said disc and to the periphery and undersurface of said flange.

4. The combination set forth in claim 1 in which the side wall of said first reduced diameter portion is cylindrical and said valve member has a further reduced diameter portion extending axially outward from said first reduced diameter portion defining said abutment surface having its periphery adapted to move against said valve seat, said further reduced diameter portion defining a plane surface, the outer surface of said bladder adjacent the portion thereof bonded to said side wall being in substantially the same plane as said plane surface of said further reduced diameter portion.

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5. The combination set forth in claim 4 in which a groove is provided in said abutment surface to provide communication between said liquid port and the associated chamber.

6. As an article of manufacture, a bladder for a pressure vessel, said bladder being of deformable material and having an opening at one end and being closed at its other end, said closed end being axially aligned with said opening, a valve member molded in the closed end of said bladder and axially aligned therewith, said valve member comprising a disc having a reduced diameter portion extending axially outward therefrom defining a laterally extending annular flange, said reduced diameter portion having a side wall to which the bladder material is bonded, said valve member having a further reduced diameter portion extending axially outward from said first reduced diameter portion and defining an abutment surface, said annular flange of the disc being of greater diameter than said abutment surface, said flange being interposed between the interior of said bladder and the bonded junction of the bladder material to said side wall.

7. The combination set forth in claim 6 in which a groove is provided in said abutment surface extending inwardly from the outer periphery thereof.

8. The combination set forth in claim 6 in which a layer of bladder material extends over the surface of said disc and around the periphery and undersurface of said flange and said bladder material is bonded to the surface of said disc and to the periphery and undersurface of said flange. 

1. A pressure vessel comprising a container of rigid material having two ports, one of said ports being axially aligned with said container and defining a liquid port, a deformable bladder secured in said container and separating said two ports from each other to define two variable volume fluid receiving chambers, one of said chambers being in communication with said liquid port, said bladder extending axially in said container and being closed at one end, means to charge said bladder with gas under pressure through the other of said ports, the portion of the container adjacent the periphery of the liquid port defining a valve seat, a valve member molded in the closed end of said bladder and axially aligned therewith adapted to move against said valve seat to close said liquid port, said valve member comprising a disc having an abutment surface adapted to engage said valve seat and having a reduced diameter portion extending axially outward therefrom defining a laterally extending annular flange of greater diameter than the abutment surface of said disc, said reduced diameter portion having a side wall to which the bladder material is bonded, said flange being interposed between the interior of said bladder and the bonded junction of the bladder material to said side wall.
 2. The combination set forth in claim 1 in which the periphery of said flange is rounded.
 3. The combination set forth in claim 1 in which a layer of bladder material extends over the surface of said disc and around the periphery and undersurface of said flange and said bladder material is bonded to the surface of said disc and to the periphery and undersurface of said flange.
 4. The combination set forth in claim 1 in which the side wall of said first reduced diameter portion is cylindrical and said valve member has a further reduced diameter portion extending axially outward from said first reduced diameter portion defining said abutment surface having its periphery adapted to move against said valve seat, said further reduced diameter portion defining a plane surface, the outer surface of said bladder adjacent the portion thereof bonded to said side wall being in substantially the same plane as said plane surface of said further reduced diameter portion.
 5. The combination set forth in claim 4 in which a groove is provided in said abutment surface to provide communication between said liquid port and the associated chamber.
 6. As an article of manufacture, a bladder for a pressure vessel, said bladder being of deformable material and having an opening at one end and being closed at its other end, said closed end being axially aligned with said opening, a valve member molded in the closed end of said bladder and axially aligned therewith, said valve member comprising a disc having a reduced diameter portion extending axially outward therefrom defining a laterally extending annular flange, said reduced diameter portion having a side wall to which the bladder material is bonded, said valve member having a further reduced diameter portion extending axially outward from said first reduced diameter portion and defining an abutment surface, said annular flange of the disc being of greater diameter than said abutment surface, said flange being interposed between the interior of said bladder and the bonded junction of the bladder material to said side wall.
 7. The combination set forth in claIm 6 in which a groove is provided in said abutment surface extending inwardly from the outer periphery thereof.
 8. The combination set forth in claim 6 in which a layer of bladder material extends over the surface of said disc and around the periphery and undersurface of said flange and said bladder material is bonded to the surface of said disc and to the periphery and undersurface of said flange. 